Oh, deer! How to keep them from destroying your garden

The only really reliable way to control deer is a fence. (Courtesy of John Scariot)

As many Marin gardeners know, deer can be very destructive. They feast on a wide variety of edible and ornamental plants and trees, trample small plants and chomp others to the ground. Since they usually forage at dawn, dusk and at night, missing vegetation, hoof prints or droppings may be the only evidence of their presence.

Damage may be seasonal in some areas and year-round in others. In Marin, we frequently see signs of browsing in spring when blossoms and fresh growth tempt doe and fawns out looking for a meal. New growth and plants recently from the nursery are particularly alluring.

Deer often return in the fall, when natural habitats can be parched and dry, and irrigated gardens offer moisture and greenery. Fall is also mating season, and stags may sharpen their antlers against tree trunks, sometimes seriously wounding young trees.

So, what can you do? Deer management is notoriously difficult. Feeding patterns may vary from herd to herd and sometimes from year to year. Even plants deer normally ignore may become targets when natural food sources are scarce, like during a drought.

Though challenging, the best time to take action is when you first see signs of damage. Deer are creatures of habit and often adopt a regular path for nightly dining. Do what you can right away to discourage them from visiting your house on a routine basis.

The only really reliable control is a fence. Deer usually will not jump a 7- to 8-foot fence, except on slopes, where 10 to 11 feet is recommended. Fences may be made of high-tensile wire or mesh, securely fastened to the ground to prevent crawling underneath. Alternatively, individual plants or trees may be fenced, particularly young ones or those, such as roses, that deer find irresistible.

If you dislike fencing, either because of expense or because you don’t want to live behind a barrier, one compromise is to fence just part of your yard. Protect vegetation that deer find most attractive, leaving the rest open for habitat.

A second strategy to minimize deer damage is to use vegetation they do not like and tend to avoid. While nothing is “deer-proof,” some plants are more resistant than others. Discovering what your local herd finds distasteful may require some experimentation, but there are a few guidelines.

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Deer generally avoid plants with toxic foliage, such as oleanders, daffodils, poppies and anything in the nightshade family. They are usually repelled by plants with a strong herbal or medicinal smell, including lavender, sage (Salvia), thyme, rosemary, lantana and catmint.

Plants with fuzzy leaves, like lamb’s ear (Stachys), are usually left alone, as are those with prickly ones, like barberries (Berberis) and gooseberries. Tough, leathery foliage, sported by manzanitas and viburnums, is unappealing. Ferns and ornamental grasses are generally ignored, as are California natives, which are widely available in their natural habitat.

Here are places to find more detailed lists of “deer-resistant” plants:

There are a few more suggestions to discourage deer. Avoid planting things they love (those roses) that draw them into your garden. Once there, they may munch on everything else along the way. Also, reducing water on established plants will intensify any naturally off-putting odor they may have.

And last, there are chemical repellants that can be effective, though not fool-proof. They require diligence and regular application to maintain their potency, so they are perhaps most appropriate for limited areas, a few prized plants, or those fresh from the nursery. Some may need to be reapplied after rain in order to maintain protection.

Repellants are designed to deter deer with objectionable odors or tastes. Many are made from soaps or egg products and are low in toxicity, but they may not be approved for use on edible gardens. Read directions carefully before use.

The UC Marin Master Gardener column is written by UC Marin Master Gardeners, who are sponsored by the University of California Cooperative Extension. For questions about gardening, plant pests or diseases, call 415-473-4204 from 9 a.m. to noon, and 1 to 4 p.m. weekdays, bring in samples or pictures to 1682 Novato Blvd., Suite 150B, Novato, or email helpdesk@marinmg.org